Cede ⇧⌘T to Show Tab Bar — window tabbing stays enabled, Show Trash unchorded

Show Trash's ⇧⌘T collided with the Show Tab Bar item macOS injects into
multi-window apps. Settled: tabbing is kept as a system affordance (each
tab a full board window, per-board frames applying when standalone) and
Show Trash ships with no default chord, assignable via the remap path.

Claude-Session: https://claude.ai/code/session_01HJ7PhFNmQ19bvy9RMD6GSb

DESIGN/03-board-ui.md

@@ -62,7 +62,7 @@ Deletion is a two-stage, Finder-style story: ⌫ tombstones (01-storage-format.m
 
 - **Rendering**: trailing (rightmost) position, visually distinct — dimmed/hatched header, trash SF Symbol, count badge; no new-card button; not draggable, not resizable, excluded from lane reordering. It spans a **fixed one width unit** — no `width` frontmatter, and neither the stepper nor the edge drag applies — consumed only while shown: Show/Hide Trash is a re-divide trigger (Layout above), dividing the window across lane units + 1. A small window compresses like any lane add — accepted, not floored.
 - **Contents**: the board's tombstoned cards, sorted by `deleted` timestamp (newest first). **The sort is fully deterministic** (settled — the trash's order is load-bearing for input: arrow walks, ⇧-ranges, and the rubber band all read it, 04-interactions.md): ties — a multi-card ⌫ stamps one second onto N cards — break by folder name, ascending; an entry whose `deleted` value doesn't parse (01-storage-format.md's unusable-timestamp rule) sorts as *oldest*, after every dated entry, folder-name-ordered among its kind — a corrupt stamp must not outrank fresh deletions for the trash's most prominent rows. Lane entries interleave in the same single ordering by their own `deleted` stamp. A tombstoned *lane* appears as a single restorable entry — its cards were hidden with it, not individually tombstoned, and it restores as a whole. **The ancestor walk is absolute here too** (settled): the lane's single entry subsumes *everything* beneath it — a card that carries its own `deleted:` under a tombstoned lane has **no row of its own** (01-storage-format.md's consumer rule, no trash carve-out; 02-architecture.md's effective liveness agrees: such a card renders nowhere). The entry's card count counts what Put Back returns to the board — cards without their own flag; individually tombstoned descendants aren't in that number, since they come back to the *trash* (below).
-- **Visibility**: hidden by default; **View ▸ Show Trash** toggles it (⇧⌘T; stable title with checkmark state, per 04-interactions.md's configurable-bindings rules). Transient board-scoped state, held in the BoardStore (02-architecture.md; one board window per board, so board-scoped and per-window coincide today) — resets to hidden on open, not persisted (visiting the trash is an errand, not a layout choice). Hidden trash is invisible to search; shown, it participates in the filter like any lane.
+- **Visibility**: hidden by default; **View ▸ Show Trash** toggles it (no default chord — ⇧⌘T belongs to the system's Show Tab Bar, window tabbing staying enabled, 11-command-nexus.md; stable title with checkmark state, per 04-interactions.md's configurable-bindings rules). Transient board-scoped state, held in the BoardStore (02-architecture.md; one board window per board, so board-scoped and per-window coincide today) — resets to hidden on open, not persisted (visiting the trash is an errand, not a layout choice). Hidden trash is invisible to search; shown, it participates in the filter like any lane.
 - **Put Back** (context menu, Finder vocabulary; ⌘⌫ on a tombstoned selection — Finder's own symmetry): removes `deleted:` — the item reappears in its lane at its old `order` (ties break deterministically). **Putting back a lane splits its contents by flag** (settled): cards hidden with the lane return to the board with it; cards carrying their own `deleted:` stay tombstoned — their rows reappear in the trash. Recovering one of those is deliberately two steps: Put Back the lane, then Put Back the card (the one-step cascade was considered and rejected — the card has no row to act on while its lane is tombstoned, per Contents above). Restore fidelity is perfect because nothing ever moved.
 - **Drag-to-restore**: dragging a card out of the trash into one of its own board's lanes restores it at the drop position (key removed, `order` set, folder moved only if the destination lane differs). Dropped on another board it follows the drag locality model (04-interactions.md) — a live copy by default, the tombstoned original staying put; ⌘-drag for the true restore-move.
 - **Keyboard, selection, and clipboard semantics** inside the shown trash (navigation, no mixed live/tombstoned selections, copy-out-only clipboard, inert moves) are specified in 04-interactions.md ▸ The trash, keyboard-first.